Ending the week on a high note are today’s midday gainers Ambit Biosciences Corp (NASDAQ:AMBI), Nimble Storage Inc (NYSE:NMBL) and ISIS Pharmaceuticals, Inc. (NASDAQ:ISIS). On the losing end this Friday are dELiA*s, Inc. (NASDAQ:DLIA), RetailMeNot Inc (NASDAQ:SALE) and 21Vianet Group Inc (NASDAQ:VNET).

chart_1 (25) RetailMeNot

Ambit Biosciences Surges, Isis Pharmaceutical Nears 52-Week High

The price of Ambit Biosciences Corp (NASDAQ:AMBI) jumped +11.51% earlier in the day today, rendering it the day’s top midday gainer. Billionaire investor George Soros owns 25,000 shares of the biopharmaceuticals company.

Following AMBI is Nimble Storage Inc (NYSE:NMBL). Its share price surged +9.93% early in the day. The company was updated upgraded to a buy rating by Wunderlich earlier in the week – likely a factor in the jump. Hedge fund Tiger Global has a 250,000-share stake in the firm.

ISIS Pharmaceuticals, Inc. (NASDAQ:ISIS), also a Soros investment pick, watched its price surge +9.62% midday today, nearing a 52-week high. The company announced yesterday that its experimental blood thinner was more effective than another more commonly prescribed drug, giving its share price a boost.

Google Algorithm Reshuffle Causes RetailMeNot to Hit All-Time Low

RetailMeNot Inc (NASDAQ:SALE) fell -7.49% midday today – the result of a report revealing that Google’s search algorithm has made results leading to the coupon site 33% less visible. The stock hit an all-time low of $22.45 earlier in the day. Billionaire George Soros holds 1.01 million SALE shares.

Following RetailMeNot is 21Vianet Group Inc (NASDAQ:VNET), the price of which dropped -5.27% today. The Chinese data center operator reported major net losses in Q1 despite an increase in net revenues. Soros picked up a position in VNET during the first quarter of the year.

Also ending this week on a low note is dELiA*s, Inc. (NASDAQ:DLIA), which rounds out this Friday’s list of midday losers. A Tiger Global holding, the retailer’s stock price dipped -4.11%. It is down -21.25% in 2014.